Random "xkcd: what if?"

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Random \"xkcd: what if?\"",
  "description": "Implements the random button (which exists on the xkcd homepage) on the \"what if\" section of xkcd.",
  "version": "2.0.1",
  "content_scripts": [
    {
      "exclude_globs": [],
      "include_globs": [
        "*"
      ],
      "js": [
        "main.user.js"
      ],
      "matches": [
        "*://*.whatif.xkcd.com/*",
        "*://*.what-if.xkcd.com/*"
      ],
      "run_at": "document_end"
    }
  ],
  "converted_from_user_script": true,
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  }
}